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2 years ago

Utherford proposed that atoms have positive nuclei which statement correctly describes the nucleus of an atom?

1 answer:

3 0

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 gold foil experiment.

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_Mg+_O2=_MgO<br> Balance out this reaction above

Ira Lisetskai [31]

2 Mg + 1 O2 = 2 MgO.

8 0

2 years ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$

[In-]/[HIn] = 1.58x10⁻⁵

ii) pH = 2.1

2.1 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -7.6

[In-]/[HIn] = $10^{-7.6}$

[In-]/[HIn] = 2.51x10⁻⁸

iii) pH = 7.8

7.8 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -1.9

[In-]/[HIn] = $10^{-1.9}$

[In-]/[HIn] = 0.0126

iv) pH = 11.5

11.5 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = 1.8

[In-]/[HIn] = $10^{1.8}$

[In-]/[HIn] = 63.10

6 0

2 years ago

Gold is formed in pure state in nature but not iron,why?

ss7ja [257]

Gold is found in pure state in nature but not the iron because gold is un-reactive metal, so it does not react with other element in normal condition but iron is reactive metal so it reacts with atmospheric oxygen in presence of moist (water) to form oxide.

Explanation:

I hope it'll help you.

5 0

2 years ago

Read 2 more answers

PLZ help Asap!!!!!! I WILL GIVE BRAINLIEST!!!

Sergeu [11.5K]

Answer: Chosen landforms are:

1) Hill

2) Mountain

3) Plateau

4) Valley

Explanation:

1) Hill is an elevated location smaller than a mountain. Location: Land

2) Mountain is a large mass of earth and rock, rising above the common level of the earth or adjacent land, usually given by geographers as above 1000 feet in height (or 304.8 metres).

Location: Land or Water

3) Plateau is a largely level expanse of land at a high elevation. It is also known as tableland.

Location: Land

4) Valley is an elongated depression between hills or mountains, often with a river flowing through it.

Location: Land or Water

6 0

2 years ago

What is the answer to this question

kvasek [131]

Answer:

b. double bonds, triple bonds, carbon atoms,and hydrogen atoms.

Explanation:

<h2>please mark me brainliest</h2>

3 0

2 years ago